The present embodiments relate to registering data representing a patient region. For example, a two-dimensional (2D) fluoroscopic image is registered with preoperative Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) data.
2D X-ray fluoroscopy is routinely used for vascular interventions and for cardiac catheterization. Fluoroscopy is used for real-time monitoring of the procedure and catheter location visualization. However, 2D fluoroscopic images lack detailed anatomical information due to the incapability of X-ray in distinguishing among soft tissues.
In order to augment the doctor's visualization of the body anatomy, for example, in the arterial fibrillation procedures, Intracardiac Echo (ICE) is used as an intra-operative modality to provide real-time cross-sectional ultrasound images. The drawback of ultrasound images compared to the high-quality preoperative volumetric data, such as Computed Tomography (CT) and Magnetic Resonance Imaging (MRI), is that the field of view is limited to local regions and the image quality is inferior with much lower spatial resolution. It is preferred to have CT and/or MRI data to provide high-quality global-view visualization of the body anatomy.
The high-resolution preoperative CT and/or MRI data may be fused with the intra-operative 2D fluoroscopy through 2D3D registration techniques. 2D3D registration techniques are generally intensity-based, centerline-based, and landmark-based, all of which typically require that the vessels of interest in fluoroscopy be opacified by injecting contrast agent into the patient. Without the contrast agent to highlight the vessels, intensity and centerline-based 2D3D registration in a robust manner is difficult. For landmark-based registration, accurate manual selection of 3D points represented by the volumetric data is not easy, and it is not always possible to identity the landmarks in the 2D fluoroscopy image without highlighting the region of interest via contrast agent. The clear structures in the fluoroscopy images, such as catheters and other devices, may not be present in the preoperative 3D volumes. Contrast agent administration may be undesired for patients' safety.